Regeneron (NASDAQ: REGN) spokesperson Peter Dworkin, while declining comment on earlier takeover chatter involving Sanofi (NYSE: SNY), did say that the two companies have a solid working relationship and have stated it would be advantageous to keep the relationship going as it is now, as separate companies.

Sanofi is Regeneron's largest shareholder currently. There is a standstill agreement in place preventing Sanofi from acquiring more than 30% of Regeneron's shares.